1. Field of the Invention
This invention relates to an information recording medium, an information recording and/or reproducing method, and an information recording and/or reproducing apparatus.
2. Description of the Related Art
Various kinds of high-density recording methods have been known. Magnetic recording and optical recording are typical among such methods. In magnetic recording, a recording wavelength is determined according to the restriction of a device, such as a magnetic head or the like, used in a recording and reproducing operation. A recording wavelength of about 1 .mu.m is a limit in magnetic recording. In optical recording, a recording wavelength is limited by the diameter of a light beam used in a recording and reproducing operation. A wavelength of about 1-0.5 .mu.m is a limit in optical recording.
Recently, STM's (scanning tunnel microscopes) have been developed. In an STM, the state of the surface of a solid can be analyzed with a horizontal resolution of a few Angstroms and a vertical resolution of at least one Angstrom (G. Binnig et al. Helvetica Physica Acta, 55, 726 (1982)).
There have been some proposals to record and reproduce projections and recesses, or changes in the electronic state on the order of nanometers on the surface of a recording medium using the principle of the STM (Japanese Patent Application Public Disclosure (Kokai) Nos. 63-161552 (1988) and 63-161553. These documents are priority applications for U.S. patent application Ser. No. 668,399).
In producing a recording/reproducing apparatus using the above-described principle, higher precision than in producing a conventional apparatus is needed. In pursuing higher precision, since the resolution of an observed image depends on the shape of the distal end of a probe used in an STM apparatus, it has become necessary to minimize the influence of distortion of a signal due to a change in the shape of the distal end of the probe in the information recording/reproducing apparatus utilizing the principle of the STM.